Method and apparatus for recording jaw movements

ABSTRACT

The disclosed method consists in measuring the movements of the lower jaw (mandible) relative to the upper jaw by selecting two points a fixed distance apart on the horizontal axis of rotation of the subject&#39;&#39;s mandible, one on each side of subject&#39;&#39;s head and at substantially equal distances from the subject&#39;&#39;s head; recording the positions of the points relative to the subject&#39;&#39;s head when the jaws of the subject are in centric relation; and when the subject&#39;&#39;s mandible moves from centric relation, continuously measuring in three dimensions the position of each of the points relative to the position that it occupied in centric relation.

United States Patent Lee [54] METHOD AND APPARATUS FOR RECORDING ,IAWMOVEMENTS [72] Inventor: Robert L. Lee, 22937 Grand Terrace Road,Colton, Calif. 92324 [73] Assignees: Robert L. Lee; Arlene M. Lee; GeneW. Arant, Los Angeles, Calif. part interest to each [22] Filed: June 24,1969 [21] Appl. No.: 836,062

Related US. Application Data [62] Division of Ser. No. 569,472, Aug, 1,1966, Pat. No.

LEGEND .2

TERM/M4 AVA/6E 4X/5 CG'VPVLE WAIT 7277700 cE/vre/c eex seavce 747700 f/5 m/NrV/7 r1 1 Peh.2,1l972 Primary Examiner-Robert PeshockAttorneyBeehler, Arant & Jagger [57] ABSTRACT The disclosed methodconsists in measuring the movements of the lower jaw (mandible) relativeto the upper jaw by selecting two points a fixed distance apart on thehorizontal axis of rotation of the subjects mandible, one on each sideof subjects head and at substantially equal distances from the subject'shead; recording the positions of the points relative to the subjectshead when the jaws of the subject are in centric relation; and when thesubjects mandible moves from centric relation, continuously measuring inthree dimensions the position of each of the points relative to theposition that it occupied in centric relation.

29 Claims, 5 Drawing Figures (GNOME ham/7 PMEWEDFEBM mm 3, M3 m 3 E3 2sum 2 UF 3 HNVENTOR, @057 1.. LEE

PMEWEDHBE? W 30 38 332 SHEET 3 BF 3 nunmnuun INVENTOR. EOE/QT L. LEE

SUMMARY OF THE INVENTION The disclosed jaw movement recording apparatusincludes an upper face bow and a lower face bow, each having laterallypositioned transducer elements for measuring the relative movementbetween the jaws. Each face bow is a rigid structure which supports itstwo lateral transducer elements in a fixed spatial relationship to eachother as well as to the associated jaw of the subject. Each face bow issupported from the corresponding jaw of the subject by support meanswhich is adjustable in three dimensions, in terms of both position andangle.

In the preferred form of the apparatus each transducer includes a solidrecord member which is attached to the upper face bow, and a styluswhich is attached to the lower face bow.

In the preferred form of the apparatus there is also a third transducerlocated in a frontal position, including a solid record member attachedto the upper face bow and a stylus attached to the lower face bow. Thetwo lateral stylii are horizontally disposed and have their longitudinalaxes located on a common center line, while the stylus of the frontalrecorder is vertically disposed. The lateral record members have theirrecording surfaces vertically aligned and facing outward while thefrontal record member has its recording surface horizontally aligned andfacing downward.

According to the present invention the movements of the axis of themandible (lower jaw) in its translated or rotated positions are measuredrelative to its location in the centric position. According to thepreferred form of the invention transducer devices are utilized whichare capable of measuring three-dimensional movement; that is to say, themovement of a single point of information is recorded in threedimensions, rather than recording the movements of two different pointsin two dimensions each. Furthermore, in accordance with the method ofthe present invention it is preferred to locate two transducers inlateral positions so that the points being measured are preciselyaligned with the horizontal axis of rotation of the mandible. Morespecifically, an initial or reference position measurement is made whenthe mandible is in centric position so that the axis of the mandiblecoincides with what may be referred to as the terminal hinge axis, oraxis of the maxilla. Thereafter as the mandible moves into translatedand/or rotated positions the movements of two information points on itsextended axis are measured relative to their original (centric position)locations.

The apparatus of the present invention preferably includes for each ofthe face bows, both upper and lower, a rigid structure which is capableof supporting the lateral transducer devices at a fixed separationdistance. Each face bow is supported from a corresponding clutch bysupport means capable of three-dimensional adjustment, in terms of bothdistance and angle. The dentist who is recording the jaw movementstherefore makes hand adjustments in the position of the face bowrelative to thejaw of the subject, at the time of the initial alignment,but he does not disturb the fixed separation distance between thetransducer elements.

DRAWING SUMMARY FIG. 1 is a side view ofa dental patient on whomreference marks have been tattooed as a basis for making jaw movementrecordings;

FIG. 2 is a schematic plan view illustrating how the present inventionrecords the relative movements between the axis of the mandible and theterminal hinge axis;

FIG 3 is a perspective view illustrating the recording of the protrusivemovement of the mandible in accordance with the preferred form of theinvention;

FIG. 4 is a fragmentary perspective view of one of the drills utilizedin FIG. 3; and

FIG. 5 is a perspective view ofa presently preferred form of recordingand transfer apparatus in accordance with the invention.

IDENTIFICATION OF REFERENCED PATENT This application is a division of myprior copending application Ser. No.'569,472 filed Aug. 1, 1966, now US.Pat. No. 3,452,439 issued July 1, I969. The drawing FIGS. 1 to 4,inclusive, of this present application are identical to drawing FIGS. 1to 4, respectively, of the patent. Drawing FIG. 5 of this application isidentical to drawing FIG. 79 of the patent. In the referenced patent alower recording face bow having three recording stylii (rotating drills):is shown in FIG. 18 and also in FIGS. 50, 51, 52, and 55. Some earlierforms of the lower recording face bow, which are not now preferred, areshown in FIGS. 70, 75, 76, and 77 of the patent. A presently preferredform of the lower recording face bow is shown in FIG. 5 of thisapplication (FIG. 79 of the patent).

An upper recording face bow in accordance with the invention is shown inFIGS. 32 to 41, inclusive, of the patent. Earlier forms of the upperrecording face bow, not now preferred, are shown in FIGS. 71, 74 and 77of the patent. Another form of upper recording face bow is shown in FIG.5 of the present drawings (FIG. 79 of the patent).

Adjustable support means for supporting the face bows from therespective jaws of the subject are shown in FIGS. 5 to 17 inclusive, ofthe patent, and also to some extent in FIGS. 18, 34 and 40; and in theirassembled relationship in FIGS. 50, 51 and 52.

In the patent the alignment of the upper face bow relative to the head,and the alignment of the lower face bow relative to the upper face bow,are described in connection with FIGS. 79, 80, and 82. The presentdrawing FIG. 5 (identical to patent drawing FIG. 79) provides anincomplete showing of this alignment procedure.

The entire specification and drawing of the referenced patent areincorporated herein for the: purpose of disclosing the presentinvention.

What is claimed is:

1. The method of measuring jaw movements of a human subject for purposesofdentistry, comprising the steps of:

selecting two points a fixed distance apart on the horizontal axis ofrotation of the subjects mandible, one on each side of the subjects headand at substantially equal distances from the subjects head;

recording the positions of said points relative to the subject's headwhen the jaws of the subject are in centric relation;

and when the subjects mandible moves from centric relation, continuouslymeasuring in three dimensions the position of each of said pointsrelative to the position that is occupied in centric relation.

2. The method of claim 36 wherein a third point is selected in front ofthe subjects head in a fixed position relative to said two points, theposition of said third point also being recorded when the jaws of thesubject are in centric relation, and its position being continuouslymeasured thereafter as the subjects mandible moves from the centricrelation.

3. A method of recording relative movements of the jaws of a humansubject, comprising the steps of:

selecting a pair of three-dimensional movement recording devices, eachof said recording devices including a record member capable of havingphysical impressions formed therein, and an associated stylus capable offorming such impressions;

positioning said recording devices in laterally displaced positions onrespective sides of the subjects head;

fixedly securing said record members to each other and to the subjectsupperjaw to move therewith; fixedly securing said stylii to each otherand lower jaw to move therewith;

while the subjects jaws are in centric relation, adjusting thesecurements of said stylii so as to insert said stylii into said recordmembers to thereby form initial impressions;

to the subjects and, while the subjects jaws move through positionsother than centric, maintaining the recording engagement of said styliiwith said record members and at the same time maintaining a fixedseparation distance between said stylii as well as a fixed separationdistance between said record members.

4. The method of claim 3 wherein said stylii are horizontally aligned,and while the subjects jaws are in centric relation the longitudinalaxes of said stylii are aligned with the extended horizontal axis ofrotation of the lowerjaw.

5. A method of recording the jaw movements of a human subject,comprising the steps of:

selecting a record member capable of having physical impressions formedtherein, and placing said record member on the extended horizontal axisof rotation of the lower jaw;

selecting an elongated stylus;

while the subjects jaws are in centric relation, aligning said styluswith the extended horizontal axis of rotation of the lower jaw andinserting said stylus into said record member to thereby form an initialimpression in said record member which represents centric;

and rigidly supporting said record member and said stylus fromrespective ones of the subjects jaws to move therewith in threedimensions, so that when the subject moves his jaws through positionsother than centric additional impressions representing such movementsare created in said record member.

6. The method claimed in claim 5 wherein said record member is formed ofa hard plastic material, and the end of said stylus has grooves formedthereon to provide a drill, said drill being drivingly rotated to createsaid impressions.

7. The method claimed in claim 5 wherein said record member is securedto the upper jaw and said stylus is secured to the lower jaw.

8. The method claimed in claim 5 wherein said stylus is horizontallydisposed and is secured to the lower jaw, said record member is securedto the upper jaw, and the longitudinal axis of said stylus is initiallyaligned with the extended horizontal axis of rotation of the lower jawand thereafter remains aligned with the axis of the lower jaw in itstranslated or rotated positions.

9. The method claimed in claim 8 wherein said record member is formed ofhard plastic material, and said stylus has grooves formed therein forproviding a drill which is drivingly rotated to create said impressions.

10. The method claimed in claim 9 wherein said stylus has ahemispherical end, said grooves being of helical configuration.

11. The method claimed in claim 8 wherein two said record members andtwo said stylii are employed, one on each side of the subjectface.

12. The method ,claimed on claim 11 wherein a fixed separation distanceis maintained between the ends of said stylii, and a fixed separationdistance is also maintained between said record members, while thesubject moves his jaws through positions other than centric.

13. A method of recording jaw movements intermediate to the bordermovements of a human subject, comprising the steps of:

selecting upper and lower face bows and securing them to the subject'sjaws;

selecting a pair of lateral recording devices and attaching them to theface bows on respective sides of the subjects face; attaching to one ofthe face bows, in front of the subjects mouth, a guide means having aslot formed therein which extends in the direction of the desiredmovements;

attaching to the other of the face bows a frontal guide pin adapted toengage said slot; and inserting said pin into said slot while at thesame time placing said recording devices in operative condition;

whereby subsequent movement of the subjects lower jaw 'will follow apredetermined path of movement which will be recorded by said recordingdevices.

14. An instrument for measuring the jaw movements of a human subject,comprising:

upper and lower face bows; means for securing said face bows to thesubjects upper and 5 lower jaws, respectively, to move therewith;

' a pair of recording devices situated on respective sides of the head,each including a record member capable of having physical impressionsformed therein, and an elongated recording stylus for forming suchimpressions; means rigidly supporting said record members from saidupper face bow at a fixed separation distance from each other and sothat they encompass the area of hinge axis movements; and means rigidlysupporting said recording stylii from said lower face bow with a fixedseparation distance between them and in precise longitudinal alignmentwith each other; said securing means for said lower face bow being bothpositionally and angularly adjustable in three dimensions so that thecommon longitudinal axis of said stylii may be precisely aligned withthe extended horizontal axis of the lower jaw of the subject when hisjaws are in centric relation.

15. An instrument as claimed in claim 14 wherein said support means foreach said stylus includes a carriage which is slidably movable foradjusting the longitudinal position of said stylus without disturbingits longitudinal alignment.

16. An instrument as claimed in claim 14 wherein said record members areformed of rigid plastic material, said stylii are grooved to formdrills, and which additionally includes drive means for rotating saiddrills to cut said rigid plastic material.

17. An instrument as claimed in claim 14 which includes means forpositioning said stylii ends, when the subjects jaws are in centricrelation, at precisely equal distances from the respective sides of thesubject's head.

18. An instrument as claimed in claim 14 wherein each of said recordmembers has an outwardly facing, vertically disposed recording surface.

19. An instrument as claimed in claim 14 which further includes a thirdrecording device which is frontally located, said third recording deviceincluding an additional record member supported from said upper face bowand an additional stylus supported from said lower face bow. v

20. An instrument as claimed in claim 19 wherein said additional stylusextends vertically upward and said additional record member has adownwardly facing, horizontally disposed recording surface.

21. In an instrument for recording jaw movements, the combinationcomprising:

a rigid face bow adapted to encircle one of the jaws of a human subject;

means for securing said face bow to the jaw to move therewith;

a pair of recording stylii carriages;

an elongated recording stylus supported from each of said carriages;

means supporting said carriages in slidable relationship to said facebow such that the longitudinal axes of said stylii are maintained inmutual alignment regardless of the positions of said carriages;

an and three-dimensional position and angle adjustment meanscooperatively associated with said face bow and said securing means andadapted to establish a selected position of said face bow relative tothe jaw.

22. The instrument claimed in claim 21 which also includes separatelocking means associated with each of said carriages 70 whereby the endsof said stylii may be locked at a fixed separation distance.

23. Jaw movement recording apparatus comprising, in com- 1 securedthereto;

three-dimensionally-adjustable means for supporting said upper face bowfrom the upper jaw;

a lower face bow having a set of stylii secured thereto;

means for supporting said stylii from said record members in apredetermined position of alignment relative thereto, thereby to supportthe weight of said lower face bow from the upperjaw;

and separate means for attaching said lower face bow to the lower jaw ina selected position of adjustment relative thereto.

24. In jaw movement recording apparatus, the combination comprising:

a rigid face bow having a generally horseshoe-shaped configuration;

a pair of transducer elements rigidly affixed to respective extremitiesof said face bow;

and threc-dimensionally-adjustable support means cooperativelyassociated with said face bow and adapted for supporting the same fromthe corresponding jaw of the patient;

said support means being adjustable so that said transducer elements maybe precisely aligned on the hinge axis of the corresponding jaw of thepatient without changing the fixed separation distance between them, therigid structure of said face bow thereafter serving to rigidly supportsaid transducer elements in their aligned relationship.

25. law movement recording apparatus as claimed in claim 24 wherein saidface bow is an upper face bow, and said support means includes an upperclutch and a pair of rods having their lower ends attached to saidclutch and their upper ends slidably positionable in respective verticalopenings in said face bow.

26. Jaw movement recording apparatus as claimed in claim 24 wherein saidface bow is a lower face bow, and said support means includes a lowerclutch, a U bolt supported from said clutch and having forwardlyprojecting legs, and a pair of position adjustment members coupling theassociated sides of said face bow to respective legs of said U-bolt.

27. In jaw movement recording apparatus, the combination comprising:

a lower clutch having a vise grip at its forward extremity;

a U-bolt having its base part horizontally disposed within said visegrip, the legs of said U-bolt projecting horizontally forwardly fromsaid vise grip to provide a parallel pair ofposition adjustment rods;

a generally horseshoe-shaped lower face bow;

and a pair of position adjustment members secured adjacent said face bowon respective sides of its lateral center, each of said memberscooperating with the associated position adjustment rod for establishinga selected positional and angular three-dimensional relationship of saidface bow to said clutch.

28. In a jaw movement recording instrument, hinge axis alignment meanscomprising an upper face bow having two rearward ends, a pair ofalignment blocks each having a lateral opening therethrough, means forfixedly attaching said blocks to respective ends of said face bow, pinsslidably received by said block openings for aligning said blockopenings and hence said upper face bow relative to a pair of marks onthe patients head, and a lower face bow having a pair of retractablehorizontal stylii insertable in respective ones of said openings foraligning said lower face bow relative to said upper face bow.

29. The method of aligning a face bow relative to the axis of themandible so as to maintain its alignment while the mandible moves,comprising the steps of:

1. fixedly positioning a first pair of physical markers relative to thecranium on respective sides of the face to indicate the hinge axis 2.selecting a face bow having a second pair of physical markers toindicate the axis 3. aligning the second pair of markers relative to thefirst pair and then fixing the position of the face bow relative to thecranium 4. guiding the mandible into centric relation position 5. whilemaintaining centric relation position, fastening the face bow relativeto the mandible 6. and thereafter releasing the face bow from thecranium so that it is free to move with the mandible.

Patent No. 332 Dated February 1972 Robert L. Lee

Inventor(s It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 53, (the last line of Claim 1) change is" Column 2, line54, (the first line of Claim 2) change "36" to 1- Q Column 3, line 53,(the first line of Claim 12) change "on" to --in-- Column 4, line 64,(the last paragraph of Claim 21) delete "an" at the commencement of theline Signed and sealed this 20th day of June 1972.

(SEAL) Attest EDWARD M.FLETCHER, JR, ROBERT GOTTSCHALK ttesting OfficerCommissioner of Patents FORM (10-69) uscoMM-oc 60376-P69 U.S. GOVERNMENTPRINTING OFFICE: 1969 0-356-334

1. The method of measuring jaw movements of a human subject for purposesof dentistry, comprising the steps of: selecting two points a fixeddistance apart on the horizontal axis of rotation of the subject''smandible, one on each side of the subject''s head and at substantiallyequal distances from the subject''s head; recording the positions ofsaid poiNts relative to the subject''s head when the jaws of the subjectare in centric relation; and when the subject''s mandible moves fromcentric relation, continuously measuring in three dimensions theposition of each of said points relative to the position that isoccupied in centric relation.
 2. The method of claim 36 wherein a thirdpoint is selected in front of the subject''s head in a fixed positionrelative to said two points, the position of said third point also beingrecorded when the jaws of the subject are in centric relation, and itsposition being continuously measured thereafter as the subject''smandible moves from the centric relation.
 2. selecting a face bow havinga second pair of physical markers to indicate the axis
 3. aligning thesecond pair of markers relative to the first pair and then fixing theposition of the face bow relative to the cranium
 3. A method ofrecording relative movements of the jaws of a human subject, comprisingthe steps of: selecting a pair of three-dimensional movement recordingdevices, each of said recording devices including a record membercapable of having physical impressions formed therein, and an associatedstylus capable of forming such impressions; positioning said recordingdevices in laterally displaced positions on respective sides of thesubject''s head; fixedly securing said record members to each other andto the subject''s upper jaw to move therewith; fixedly securing saidstylii to each other and to the subject''s lower jaw to move therewith;while the subject''s jaws are in centric relation, adjusting thesecurements of said stylii so as to insert said stylii into said recordmembers to thereby form initial impressions; and, while the subject''sjaws move through positions other than centric, maintaining therecording engagement of said stylii with said record members and at thesame time maintaining a fixed separation distance between said stylii aswell as a fixed separation distance between said record members.
 4. Themethod of claim 3 wherein said stylii are horizontally aligned, andwhile the subject''s jaws are in centric relation the longitudinal axesof said stylii are aligned with the extended horizontal axis of rotationof the lower jaw.
 4. guiding the mandible into centric relation position5. while maintaining centric relation position, fastening the face bowrelative to the mandible
 5. A method of recording the jaw movements of ahuman subject, comprising the steps of: selecting a record membercapable of having physical impressions formed therein, and placing saidrecord member on the extended horizontal axis of rotation of the lowerjaw; selecting an elongated stylus; while the subject''s jaws are incentric relation, aligning said stylus with the extended horizontal axisof rotation of the lower jaw and inserting said stylus into said recordmember to thereby form an initial impression in said record member whichrepresents centric; and rigidly supporting said record member and saidstylus from respective ones of the subject''s jaws to move therewith inthree dimensions, so that when the subject moves his jaws throughpositions other than centric additional impressions representing suchmovements are created in said record member.
 6. The method claimed inclaim 5 wherein said record member is formed of a hard plastic material,and the end of said stylus has grooves formed thereon to provide adrill, said drill being drivingly rotated to create said impressions. 6.and thereafter releasing the face bow from the cranium so that it isfree to move with the mandible.
 7. The method claimed in claim 5 whereinsaid record member is secured to the upper jaw and said stylus issecured to the lower jaw.
 8. The method claimed in claim 5 wherein saidstylus is horizontally disposed and is secured to the lower jaw, saidrecord member is secured to the upper jaw, and the longitudinal axis ofsaid stylus is initially aligned with the extended horizontal axis ofrotation of the lower jaw and thereafter remains aligned with the axisof the lower jaw in its translated or rotated positions.
 9. The methodclaimed in claim 8 wherein said record member is formed of hard plasticmaterial, and said stylus has grooves formed therein for providing adrill which is drivingly rotated to create said impressions.
 10. Themethod claimed in claim 9 wherein said stylus has a hemisphericaL end,said grooves being of helical configuration.
 11. The method claimed inclaim 8 wherein two said record members and two said stylii areemployed, one on each side of the subject''face.
 12. The method claimedon claim 11 wherein a fixed separation distance is maintained betweenthe ends of said stylii, and a fixed separation distance is alsomaintained between said record members, while the subject moves his jawsthrough positions other than centric.
 13. A method of recording jawmovements intermediate to the border movements of a human subject,comprising the steps of: selecting upper and lower face bows andsecuring them to the subject''s jaws; selecting a pair of lateralrecording devices and attaching them to the face bows on respectivesides of the subject''s face; attaching to one of the face bows, infront of the subject''s mouth, a guide means having a slot formedtherein which extends in the direction of the desired movements;attaching to the other of the face bows a frontal guide pin adapted toengage said slot; and inserting said pin into said slot while at thesame time placing said recording devices in operative condition; wherebysubsequent movement of the subject''s lower jaw will follow apredetermined path of movement which will be recorded by said recordingdevices.
 14. An instrument for measuring the jaw movements of a humansubject, comprising: upper and lower face bows; means for securing saidface bows to the subject''s upper and lower jaws, respectively, to movetherewith; a pair of recording devices situated on respective sides ofthe head, each including a record member capable of having physicalimpressions formed therein, and an elongated recording stylus forforming such impressions; means rigidly supporting said record membersfrom said upper face bow at a fixed separation distance from each otherand so that they encompass the area of hinge axis movements; and meansrigidly supporting said recording stylii from said lower face bow with afixed separation distance between them and in precise longitudinalalignment with each other; said securing means for said lower face bowbeing both positionally and angularly adjustable in three dimensions sothat the common longitudinal axis of said stylii may be preciselyaligned with the extended horizontal axis of the lower jaw of thesubject when his jaws are in centric relation.
 15. An instrument asclaimed in claim 14 wherein said support means for each said stylusincludes a carriage which is slidably movable for adjusting thelongitudinal position of said stylus without disturbing its longitudinalalignment.
 16. An instrument as claimed in claim 14 wherein said recordmembers are formed of rigid plastic material, said stylii are grooved toform drills, and which additionally includes drive means for rotatingsaid drills to cut said rigid plastic material.
 17. An instrument asclaimed in claim 14 which includes means for positioning said styliiends, when the subject''s jaws are in centric relation, at preciselyequal distances from the respective sides of the subject''s head.
 18. Aninstrument as claimed in claim 14 wherein each of said record membershas an outwardly facing, vertically disposed recording surface.
 19. Aninstrument as claimed in claim 14 which further includes a thirdrecording device which is frontally located, said third recording deviceincluding an additional record member supported from said upper face bowand an additional stylus supported from said lower face bow.
 20. Aninstrument as claimed in claim 19 wherein said additional stylus extendsvertically upward and said additional record member has a downwardlyfacing, horizontally disposed recording surface.
 21. In an instrumentfor recording jaw movements, the combination comprising: a rigid facebow adapted to encircle one of the jaws of a human subject; means forsecuring said face bow to the jaw To move therewith; a pair of recordingstylii carriages; an elongated recording stylus supported from each ofsaid carriages; means supporting said carriages in slidable relationshipto said face bow such that the longitudinal axes of said stylii aremaintained in mutual alignment regardless of the positions of saidcarriages; an and three-dimensional position and angle adjustment meanscooperatively associated with said face bow and said securing means andadapted to establish a selected position of said face bow relative tothe jaw.
 22. The instrument claimed in claim 21 which also includesseparate locking means associated with each of said carriages wherebythe ends of said stylii may be locked at a fixed separation distance.23. Jaw movement recording apparatus comprising, in combination: anupper face bow having a set of record members rigidly secured thereto;three-dimensionally-adjustable means for supporting said upper face bowfrom the upper jaw; a lower face bow having a set of stylii securedthereto; means for supporting said stylii from said record members in apredetermined position of alignment relative thereto, thereby to supportthe weight of said lower face bow from the upper jaw; and separate meansfor attaching said lower face bow to the lower jaw in a selectedposition of adjustment relative thereto.
 24. In jaw movement recordingapparatus, the combination comprising: a rigid face bow having agenerally horseshoe-shaped configuration; a pair of transducer elementsrigidly affixed to respective extremities of said face bow; andthree-dimensionally-adjustable support means cooperatively associatedwith said face bow and adapted for supporting the same from thecorresponding jaw of the patient; said support means being adjustable sothat said transducer elements may be precisely aligned on the hinge axisof the corresponding jaw of the patient without changing the fixedseparation distance between them, the rigid structure of said face bowthereafter serving to rigidly support said transducer elements in theiraligned relationship.
 25. Jaw movement recording apparatus as claimed inclaim 24 wherein said face bow is an upper face bow, and said supportmeans includes an upper clutch and a pair of rods having their lowerends attached to said clutch and their upper ends slidably positionablein respective vertical openings in said face bow.
 26. Jaw movementrecording apparatus as claimed in claim 24 wherein said face bow is alower face bow, and said support means includes a lower clutch, a U-boltsupported from said clutch and having forwardly projecting legs, and apair of position adjustment members coupling the associated sides ofsaid face bow to respective legs of said U-bolt.
 27. In jaw movementrecording apparatus, the combination comprising: a lower clutch having avise grip at its forward extremity; a U-bolt having its base parthorizontally disposed within said vise grip, the legs of said U-boltprojecting horizontally forwardly from said vise grip to provide aparallel pair of position adjustment rods; a generally horseshoe-shapedlower face bow; and a pair of position adjustment members securedadjacent said face bow on respective sides of its lateral center, eachof said members cooperating with the associated position adjustment rodfor establishing a selected positional and angular three-dimensionalrelationship of said face bow to said clutch.
 28. In a jaw movementrecording instrument, hinge axis alignment means comprising an upperface bow having two rearward ends, a pair of alignment blocks eachhaving a lateral opening therethrough, means for fixedly attaching saidblocks to respective ends of said face bow, pins slidably received bysaid block openings for aligning said block openings and hence saidupper face bow relative to a pair of marks on the patient''s head, and alower face bow having a pair of reTractable horizontal stylii insertablein respective ones of said openings for aligning said lower face bowrelative to said upper face bow.
 29. The method of aligning a face bowrelative to the axis of the mandible so as to maintain its alignmentwhile the mandible moves, comprising the steps of: